A recombinant microbial cell comprises at least one increased expressible enzyme
activity controlling anabolic metabolism of ammonia as a nutrient source, the increased
enzyme activity being an NADH-dependent activity catalysing the reaction
(a) 2-oxoglutarate+NH3+NADHglutamate+NAD or being
an activity catalysing the reaction
(b) 2-oxoglutarate+glutamine+NADH2 glutamate+NAD or being an
activity catalysing the reaction
(c) glutamate+NH3+ATPglutamine+ADP+Pi.
The increased enzyme activity is encoded by a nucleic acid coding sequence linked
to an expression signal not natively associated with the nucleic acid coding sequence
and is increased as compared to the expression of the enzyme activity when the
nucleic acid coding sequence is associated with its native expression signal.
